Happy 50th birthday, Target! The retailer celebrated its five-decade anniversary with a bash in New York last night, where celebrity fans like Naomi Watts (in a Target Merona blouse and Helmut Lang blazer), Revenge’s Christa B. Allen, Tony Bennett, Shaun White, and Josh Groban attended to toast with free-flowing Champagne to the milestone. “Who doesn’t love birthday parties!” Allen (in Donna Karan) told InStyle.com before taking in the celebrations, which included a surprise a cappella rendition of “Happy Birthday” by Grammy-winning artistAlicia Keys. Click through the gallery to see more stars at this week’s hottest parties!